ALMA observations of the most enigmatic structures in the ISM: the mystery of Nessie

Supervisor: Alvaro Hacar

Contact information: alvaro.hacar@univie.ac.at 

Expected duration: 9 months

 

Project description & Goals:

Recent Galactic Plane surveys have revealed the existence of >100pc long filaments, the so-called Giant Molecular Filaments (GMFs). Characterising the origin and evolution of these GMFs is essential to understand how most stars form in spiral galaxies. This project aims to explore one of the most prototypical GMFs in the Milky Way, the Nessie cloud. We have observed this GMF using the ALMA Compact Array (ACA) in Band 3 (93 GHz). Our observations mapped the molecular content of this cloud using a series of dense (N2H+) and diffuse (e.g. HNC) molecular tracers. This project aims to investigate the internal gas structure (integrated intensity maps) and dynamics (spectra) of this paradigmatic Nessie filament across 2 orders of magnitude in scale, between 150 and 0.1 pc. As primary goal, this project aims to obtain a physical description of gas density and motions within the Nessie filament combining some of the different molecular tracers obtained in our ACA observations.

 

Working plan & Milestones (including final thesis):

  1. Literature and introduction to the methodology
  2. ALMA observations of the Nessie region: ACA maps
  3. Dense vs diffuse gas tracers: create maps and comparisons
  4. Line intensity vs IR/continuum plots
  5. Spectral analysis: turbulence, velocity oscillations, and fragmentation (optional)
  6. Write Master Thesis

Requirements / special skills (optional): Basic background in star formation is preferred

References (optional):

Jackson et al 2010: https://ui.adsabs.harvard.edu/abs/2010ApJ...719L.185J/abstract

Goodman et al 2014: https://ui.adsabs.harvard.edu/abs/2014ApJ...797...53G/abstract